The present invention generally relates to a bracket for support of a wireline entry device adjacent a top-drive unit on an oil and gas drilling platform. More particularly, the present invention relates to a bracket or mounting system for supporting a wireline sheave assembly adjacent a top-drive of a drilling ship, platform, or rig to minimize stress on a gooseneck assembly and pressure control system.
The majority of large oil rigs operating throughout the world are using top-drive units to speed the assembly of drill string and to permit rapid, almost continuous, drilling. Wireline operations required on deep wells using these expensive rigs can be a severe bottleneck if they cannot be carried out with the expediency and efficiency which is sought by all drilling contractors. To remedy the problem of inserting a wireline in a top-drive unit, a top-entry apparatus providing a safe and effective means of inserting and manipulating a wireline in a top-drive unit has been developed and is the subject of U.S. Pat. No. 5,735,351 hereby incorporated herein by reference for background of this technology.
As the wells being drilled by top-drive units has increased and the depth of the wells being attempted by these top-drives has increased, the need for heavier and more robust wireline equipment has likewise be appreciated. Stringing wireline in well bore from above the top drive can be dangerous if the sheave and pulley system used is inadequate to support the weight of the increased wireline diameters (from {fraction (3/16)}″ to over {fraction (1/2)}″) required to go to the depths currently being drilled. Accordingly, the need for robust sheave and pulley systems increases the stresses on the wireline entry gooseneck and the pressure control systems (i.e. packing) which is required to allow the wireline to be paid out to the tubular suspended below under possible pressures.